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Re: [Qemu-devel] [PATCH v2 0/6] external backup api
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH v2 0/6] external backup api |
Date: |
Mon, 29 Feb 2016 09:54:49 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.0 |
On 29/02/2016 09:14, Markus Armbruster wrote:
> I completely agree with you that Get LBA Status cannot just reflect the
> top layer. But that's not what I meant to propose. Let me try to
> explain myself more clearly.
>
> Consider a QCOW2 image D (for delta) with a backing file B (for base).
> If you open it normally, you see "D over B". Get LBA Status should
> certainly claim the "deallocated" state only for blocks that are
> allocated neither in D nor B.
>
> However, you can also open D *without* its backing file. Then you see
> "D over nothing". Here, get LBA Status should claim "deallocated" state
> for anything not allocated in D.
Ok, this makes more sense.
The question then is whether to implement this NBD server inside QEMU,
or outside it as a separate process to which QEMU "pushes" blocks as in
the existing backup job. I would prefer the latter, so that it is
possible to implement various APIs (get block status, but also VMware or
Parallels or whatever).
Basically the same points made in
https://lists.gnu.org/archive/html/qemu-devel/2013-03/msg01969.html
still apply.
Paolo
- Re: [Qemu-devel] [PATCH v2 0/6] external backup api, (continued)
- Re: [Qemu-devel] [PATCH v2 0/6] external backup api, Fam Zheng, 2016/02/18
- Re: [Qemu-devel] [PATCH v2 0/6] external backup api, Markus Armbruster, 2016/02/19
- Re: [Qemu-devel] [PATCH v2 0/6] external backup api, John Snow, 2016/02/24
- Re: [Qemu-devel] [PATCH v2 0/6] external backup api, Paolo Bonzini, 2016/02/26
- Re: [Qemu-devel] [PATCH v2 0/6] external backup api, Paolo Bonzini, 2016/02/26
- Re: [Qemu-devel] [PATCH v2 0/6] external backup api, Denis V. Lunev, 2016/02/26
- Re: [Qemu-devel] [PATCH v2 0/6] external backup api, John Snow, 2016/02/26
- Re: [Qemu-devel] [PATCH v2 0/6] external backup api, Denis V. Lunev, 2016/02/26
- Re: [Qemu-devel] [PATCH v2 0/6] external backup api, Fam Zheng, 2016/02/26
- Re: [Qemu-devel] [PATCH v2 0/6] external backup api, Markus Armbruster, 2016/02/29
- Re: [Qemu-devel] [PATCH v2 0/6] external backup api,
Paolo Bonzini <=
- Re: [Qemu-devel] [PATCH v2 0/6] external backup api, Paolo Bonzini, 2016/02/29
- Re: [Qemu-devel] [PATCH v2 0/6] external backup api, Fam Zheng, 2016/02/29
- Re: [Qemu-devel] [PATCH v2 0/6] external backup api, Markus Armbruster, 2016/02/29